Defense Secretary James Mattis said Friday that his agency "can do better at communication" with Congress after meeting with Sen. John McCain on the deaths of the four Green Berets by Islamic State terrorists in Niger this month.

"We can do better at communication," Mattis told reporters with McCain after their meeting at the Capitol. "We can always improve on communication.

"That's exactly what we'll do."

McCain, the Arizona Republican who chairs the Senate Armed Services Committee, has called for a probe of the fatal Oct. 4 ambush and has threatened to subpoena witnesses if the White House does not cooperate.

When asked whether subpoenas remained a possibility despite meeting with Mattis, McCain responded: "Depends on whether we get the witnesses."

When the secretary was asked, he said: "If the Senate and House calls, they will get them."

Mattis declined to me more specific about the circumstances surrounding the attacks.

"The relationship that the secretary and I have goes back 20 years," McCain said. "It's one of respect and appreciation and it's one of honoring service.

"We continue to try to improve our lines of communication — and our regular meetings will be very helpful in that area."

Defense Secretary James Mattis said Friday that his agency "can do better at communication" with Congress after meeting with Sen. John McCain on the deaths of the four Green Berets by Islamic State terrorists in Niger this month.

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